Detection of gaseous ammonia at different concentrations is crucial in various fields from industrial to biomedical applications. A few decades ago, conductive polymers appeared as promising sensitive surfaces for ammonia chemoresistive sensors. However, some optimizations are still needed in order to fulfill the requirements for real-world application. In this work, we show how materials processing can be used to increase the sensitivity of organic devices and how printing technology can limit the impact of humidity on the measurements.